ENGLEWOOD, Colo. -- It was clear just how seriously the Denver Broncos were going to take their pursuit of a quarterback in free agency when John Elway made it clear both Demaryius Thomas and Emmanuel Sanders were in the team's plan for 2018.

Because, frankly, it would be difficult for the Broncos to present themselves as an attractive landing spot for a free-agent starting quarterback if either Thomas or Sanders, or both, had been caught up in the Broncos' desire to create some additional cap space.

And make no mistake: There was a time earlier in this offseason when it was not guaranteed Elway, as the team's chief football decision-maker, would bring both of those players back. Elway formally took that option off the table at the scouting combine when he said “that is the plan, yes" to questions of whether Thomas and Sanders would be the team's top receivers once again.

For Thomas that means the Broncos will pay a $4 million option bonus that engages the final two years of his contract.

But somewhat lost in the Broncos' pursuit of a potential starting quarterback in free agency -- Case Keenum will formally sign with the team when free agency opens Wednesday -- is even with Thomas' and Sanders' return they have plenty of work to do at the position because the 2017 season provided plenty of proof defenses can stifle their top two receivers if there isn't a third viable option on the field.

With the Broncos' carousel at quarterback when the team went from Trevor Siemian to Brock Osweiler to Paxton Lynch twice during the season and the struggles in pass protection, both Thomas and Sanders were limited at times as defenses simply rotated coverage to force the Broncos to throw elsewhere.

Thomas' 83 receptions and 949 yards were his lowest totals since 2011, when the Broncos ran an option-based offense with Tim Tebow at quarterback for much of the season. Sanders' 47 catches and 555 yards were his lowest totals since 2012. Sanders, who also missed four games with an ankle injury, also did not have a touchdown catch after Week 2.

"We want to have them come back and play the way they're capable of," is how Elway put it at the scouting combine. "They still have a lot of football and still (are) a top receiving pair in the league so we have high expectations, but they’ve got to come back and play a lot better."

The Broncos also have to find a third receiver, or a tight end, or both, who can take some of the attention away from Thomas and Sanders. It is one of the items on their to-do list with free agency set to officially open Wednesday afternoon as well as with 11 picks at their disposal in the April draft.

With tight end Virgil Green and wide receiver Cody Latimer set to be unrestricted free agents, the Broncos haven't shown much interest in re-signing either player to this point. The Broncos also did not tender an offer to wide receiver Bennie Fowler, a restricted free agent who was fourth on the team in catches this past season, so he will be a free agent Wednesday.

Remove Green, Latimer and Fowler from the equation and at the moment the Broncos would have no wide receivers on the roster who caught more than 13 passes last year beyond Thomas and Sanders.

There are wide receivers in free agency such as Donte Moncrief, Sammy Watkins and Paul Richardson available for the Broncos.

The Broncos also hope Jake Butt, who missed his rookie season recovering from a knee injury he suffered in his last game at Michigan, is ready for his moment in the offensive sun. The Broncos believed Butt was the most proficient receiver/blocker combination at the position in the 2017 draft. They still believe he can have immediate impact as an option in the scoring zone.

Coach Vance Joseph said the Broncos will address their personnel needs among the pass catchers, but he also believes if the Broncos cut down on turnovers -- only the winless Cleveland Browns had more turnovers than the Broncos' 34 last season -- the Broncos can work from more favorable field position and that would give them more options on offense as well.

“That’s not winning football," Joseph said. “If we play winning football, take care of the ball, all of our players can be in better position to do what they do best for us. But certainly we want to find playmakers."